Real Estate (Schedule of Property Disposition) (Details) - Riverview Plaza [Member] - Disposal Group, Held-for-sale, Not Discontinued Operations [Member]	6 Months Ended
Jun. 30, 2022 USD ($) ft²
Real Estate Properties [Line Items]
Location	Philadelphia, PA
GLA \| ft²	108,902
Date Sold	May 16, 2022
Sales Price	$ 34,000,000
Impairment	$ (199,000)

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

Name:	us-gaap_ImpairmentOfRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration